Adjustable venturi injector



Nov. 1, 1966 A. NIELSEN ADJUSTABLE VENTURI INJECTOR Filed June 22, 1964INVENTOR. 9004; M545! United States Patent C) 3,282,227 ADJUSTABLEVENTURE INJECTOR Adolph Nielsen, Oakland, Calif, assignor to NielsenMfg. Co., Oakland, Calif, a corporation of California Filed June 22,1964, Ser. No. 376,768 3 Claims. (Cl. 103-271) This invention relates tofluid injectors of the type which employ a venturi action to draw onefluid into a second fluid by using the kinetic energy of the secondfluid. The invention more particularly involves a double venturiconstruction of the type shown in my United States Patent No. 3,011,443,where the flow through one venturi may be adjusted to control thedrawing power of a fixed second venturi.

In brief, the present invention contemplates an injector constructionthat provides a novel arrangement of parts to control the drawing powerof a double venturi. The adjustable injector herein describedessentially comprises a housing having first and second coaxialsections, said sections being adjustably connected together in end-toendrelationship. A venturi tube mounted within the injector is supportedfrom the first section, being spaced from the inner walls of the housingto form an annular flow path therebetween. The second section provides aflow restricting surface complementary to a surface formed on theventuri tube, the two surfaces limiting the amount of fluid flow passingthrough the annular flow path. By operation of means adjustablyconnecting the first and second section in axial end-to-endrelationship, the spacing be tween complementary flow restrictingsurfaces of the tube and the second section may be adjusted. The size ofthe venturi tube and the cross-sectional area between flow restrictingsurfaces is such that the greatest flow occurs through the annular flowpath between the venturi tube and the injector housing, thecross-sectional area being considerably greater than that of the throatof the venturi tube. The velocity of fluid passing through the annularpassage increases greatly as it passes between the complementary flowrestricting surfaces, creating a region of low pressure at the dischargeend of the venturi tube. The appreciable pressure drop between theintake and discharge ends of the venturi tube tends to increase the flowof water through the tube, and correspondingly increases the amount offluid or gas drawn into the throat of the venturi tube. It will beevident that an adjustment in the connection between the first andsecond sections of the housing may be made to either increase ordecrease the velocity of fluid flow between the flow restrictingsurfaces. In making such an adjustment, there will be a correspondingchange in the pressure drop between the intake and discharge ends of theventuri tube, resulting in a change in the drawing power of theinjector.

It is a principal object of the present invention to provide anadjustable double venturi that may be easily manufactured at a lowercost than injectors of similar kind.

Another object is to provide an injector of the type describedcomprising a pair of coaxial sections which fluidly communicate with anoverlapping and slidable fit, and which are connected by an externaladjustable means.

Another object of this invention is to provide an injector of the typedescribed comprising a pair of coaxial sections and a threaded collarfor connecting said sections and permitting an adjustment in thecross-sectional area of a main flow venturi to control the drawing powerof a second venturi.

It is yet another object of the invention to provide an injector of thetype described, including a housing comprised of a pair of coaxialsections, one section having a right-hand thread and the other aleft-hand thread, said sections being adjustably connected by a collarhaving 3,282,227 Patented Nov. 1, 1966 "ice threaded inner surfacescomplementing said right and left-hand threads respectively.

Other objects of this invention will become apparent in View of thefollowing detailed description and the accompanying drawings.

In the drawings forming a part of this application and in which likeparts are identified by like reference numerals throughout the same,

FIG. 1 is a longitudinal section of a double venturi injectorconstructed in the preferred manner contemplated by this teaching;

FIG. 2 is an elevation of the injector shown in FIG. 1; and

FIG. 3 is a section taken on lines 33 of FIG. 2.

Referring to FIG. 1 of the drawings in particular, there is shown apreferred embodiment of the invention in an injector 10 connected into aflow line by a pair of threaded leads 11 and 12. Injector 10 essentiallycomprises first and second coaxial sections 13 and 14, the intake end ofsection 13 being threaded for connection to lead 11 while the dischargeend of section 14 is threadedly connected to lead 12. The near ends ofsections 13 and 14 are overlapped in a telescopic fit, the tubular end15 of section 14 being received within the sleeve 16 of section 13. AnO-ring seal 17 is provided in an inner recess formed in sleeve 16 toprevent fluid leakage between tubular end 15 and sleeve 16. Sections 13and 14 are threaded along their outer surfaces 18 and 19, respectively,and the two sections are held together by a threaded collar 20.Importantly, the threads provided on surface 18 are formed in aright-hand manner, while the threads on surface 19 are of the left-handvariety; and the inner surface of collar 20 is threaded to mate with thethreads 18 and 19. Therefore, as collar 20 is rotated in a right-handdirection relative to the end of section 13 the two sections will bedrawn together, the tubular end 15 sliding within sleeve 16. A rotationof collar 20 in the opposite direction will, of course, produce theopposite effect and move sections 13 and 14 axially away from eachother.

In most other respects injector 10 is of a conventional constructionhaving a venturi tube 21 disposed within the main flow passage 22 of theinjector. The venturi tube comprises a pair of venturi members 23 and 24mounted by threading each into an opening of a boss 25 formed integrallywith section 13. Venturi tube 21 has a restricted throat portion 26within the boss 25 which communicates with an injection passage 27formed through the boss and fluidly connected to the end of an inletconduit 28.

The interior of section 14 is defined in part by an upstream surface 29,a tapered surface 30 and a restricted passage 31. Furthermore, it willbe noted that venturi member 23 is formed with a radially enlargedportion 32 near its discharge end, providing a tapered surface 33 thatcomplements and cooperates with the tapered surface 30 to form a flowrestricting passageway therebetween. The radially enlarged portion 32 isalso provided with a tapered surface 34 extending radially inward and inan upstream direction relative to the body thereof, said tapered surfacetending to reduce the turbulence of fluid flowing through the annularspace between the venturi member and surface 29.

When properly assembled, the discharge end 35 of venturi member 23 isdisposed within the restricted throat 31. This is true regardless of thelongitudinal adjustment that may be effected by turning collar 20 andslidably adjusting the axial relationship and connection of sections 13and 14. With such an arrangement, the fluid passing between surfaces 30and 33 must necessarily pass into throat 31 before coming into contactwith the end 35 of venturi member 23. There can then be no build up ofpressure atthe discharge end 35 of the venturi.

In operation, and as fluid is pumped through injector the greatest flowwill occur in the annular space between venturi tube 21 and the innersurfaces of sections 13 and 14, since the cross-sectional area of theannular passage between surfaces 30 and 33 is considerably greater thanthe throat 26 of the venturi tube. Moreover, as the fluid passes throughthe annular passage between the flow restricting surfaces 30 and 33 itsvelocity greatly increases, thus creating a region of low pressure atthe discharge end 35 of venturi member 33 and resulting in anappreciable pressure drop between the intake and discharge ends ofventuri tube 21. The resulting increase in the pressure drop augmentsthe natural flow of water through the venturi tube, and correspondinglyincreases the drawing power of tube 21, causing a greater amount offluid or gas to be drawn in through the injector. Expressed in anotherway, injector 10 has a double venturi effect, the main water flow(passing between surfaces 30 and 33) serving to boost the water flowthrough the throat of venturi tube 21. This principle of operation isessentially the same as that of the fluid injector described in myearlier United States Patent No. 3,011,443.

An adjustment in the drawing power of injector 10 may be produced simplyby rotating collar 20 in either clockwise or counter-clockwise fashion.Since venturi member 23 is supported from section 13, surfaces 30 and 33will be positioned either in closer proximity or more distant from eachother by the mere turning of collar 20.

An adjustment in the cross-sectional area betwen surfaces 30 and 33will, of course, produce a variation in the fluid flow through theannular passage which those surfaces define. Increasing the size of thepassage, decreases the velocity of the Water passing therethrough (whilealso decreasing the pressure drop between the intake and discharge endsof venturi tube 21). On the other hand, a decrease in thecross-sectional area of the passageway defined by surfaces 30 and 33will increase the rate of fluid discharged into the .throat 31, therebyincreasing the pressure drop across the venturi tube 21 and increasingits drawing power.

Although not shown, it is especially contemplated that a pair of setscrews may be used to lock collar 20 to one or both of the threaded ends18 and 19. While such screws are not essential, they may provideinsurance against inadvertent turning of collar 20.

It is to be realized that an adjustment in the connection betweensections 13 and 14 inherently produces a change in overall length of theinjector 10. However, this change in length is very small, involving adimensional change of only approximately one-quarter of an inch. Flowlines in which injectors of this kind are normally used usually toleratea change in length far in excess of one-quarter of an inch, and for thisreason there would be no difliculty in making an adjustment of injector=10 while it is being used and connected into a flow line.

Although a preferred embodiment of this invention has been illustratedand described, various changes may be made without departing from thespirit of the invention or the scope of the attached claims, and each ofsuch changes is contemplated.

What I claim and desire to secure by Letters Patent is:

1. An adjustable injector comprising a housing having first and secondcoaxial sections adjustably connected in end-to-end relation; a venturitube mounted within said housing and supported from said first section,said tube being spaced from the inner Walls of said housing to form anannular flow path therebetween; said second section and tube havingcomplementary flow restricting surfaces limiting the amount of fluidflow passing through said annular flow path; and a threaded collaradjustably connecting said first and second sections in axialrelationship for adjusting the spacing between said complementary flowrestricting surfaces.

2. The adjustable injector of claim 1 wherein the outer surfaces of saidcoaxial sections are threaded, one section having a right-hand threadand the other section a lefthand thread; and wherein said threadedcollar has threaded inner surfaces complementing said right-hand andlefthand threads respectively.

3. An adjustable injector comprising a housing having first and secondcoaxial sections adjustably connected in end-to-end relation, the outersurfaces of said coaxial sections being threaded, one section having aright-hand thread and the other section a left-hand thread, saidsections providing a flow passage therethrough having an intake at theend of said first section and a discharge at the end of said secondsection; a tubular member mounted in said flow passage and supportedfrom said first section, said tubular member having a venturi passagetherethrough coaxial with said flow passage and forming an annular flowspace With the inside surface of said housing; an injection passageformed through said first section and tubular member into the throat ofsaid venturi passage; means forming a restriction on the inside surfaceof said second section adjacent to but forward relative to the dischargeend of said tubular member, said restriction forming means also definingan annular passage with the outer surface of said tubular member, saidannular passage converging toward the discharge of said second section;and a collar having threaded inner surfaces complementing saidright-hand and left-hand threads, respectively, adjustably connectingsaid first and second sections in axial relationship for adjusting thecross-sectional area of said annular passage.

References Cited by the Examiner UNITED STATES PATENTS 136,780 3/1873Smith 2301l2 X 2,938,464 5/1960 Nielsen 103262 X 3,011,443 12/1961Nielsen l03273 X MARK NEWMAN, Primary Examiner.

WARREN E. COLEMAN, Examiner.

1. AN ADJUSTABLE INJECTOR COMPRISING A HOUSING HAVING FIRST AND SECONDCOAXIAL SECTIONS ADJUSTABLY CONNECTED IN END-TO-END RELATION; A VENTURITUBE MOUNTED WITHIN SAID HOUSING AND SUPPORTED FROM SAID FIRST SECTION,SAID TUBE BEING SPACED FROM THE INNER WALLS OF SAID HOUSING TO FORM ANANNULAR FLOW PATH THEREBETWEEN; SAID SECOND SECTION AND TUBE HAVINGCOMPLEMENTARY FLOW RESTRICTING SURFACES LIMITING THE AMOUNT OF FLUIDFLOW PASSING THROUGH SAID ANNULAR FLOW PATH; AND A THREADED COLLARADJUSTABLY CONNECT-